664706489 has 2 divisors, whose sum is σ = 664706490. Its totient is φ = 664706488.

The previous prime is 664706461. The next prime is 664706491. The reversal of 664706489 is 984607466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 416486464 + 248220025 = 20408^2 + 15755^2 .

It is a cyclic number.

It is not a de Polignac number, because 664706489 - 2¹² = 664702393 is a prime.

It is a Sophie Germain prime.

Together with 664706491, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (664706459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332353244 + 332353245.

It is an arithmetic number, because the mean of its divisors is an integer number (332353245).

Almost surely, 2^664706489 is an apocalyptic number.

It is an amenable number.

664706489 is a deficient number, since it is larger than the sum of its proper divisors (1).

664706489 is an equidigital number, since it uses as much as digits as its factorization.

664706489 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1741824, while the sum is 50.

The square root of 664706489 is about 25781.9023541708. The cubic root of 664706489 is about 872.7234377656.

The spelling of 664706489 in words is "six hundred sixty-four million, seven hundred six thousand, four hundred eighty-nine".